1. Field of the Invention
This invention relates to an industrial truck, in particular a lift tuck, with a drive section and a load section that can be raised relative to the drive section. The load section has at least one wheelarm which is provided with at least one load roller. A linkage that is in an operative connection with the load roller and a lever system that actuates the linkage are provided to lift the wheelarm.
2. Description of Related Art
Industrial trucks with wheelarms are used to lift pallets by driving the wheelarms under the pallet and then lifting the wheelarms to lift the pallet. For this purpose, the load section is raised or lowered relative to the drive section. Wheelarm levers in which the load rollers are mounted are located so that they can swivel on the wheelarms and are actuated by the lever system and the linkage to lift the wheelarms. On low-lift trucks or order pickers, a lifting movement of this type is called a low lift, while on high-lift trucks with an additional lifting frame, it is called the initial lift.
Lift trucks with load rollers located on the wheelarms, which are actuated by a linkage and a system of levers, are described, for example, in EP 1 690 823 B1 or DE 10 2009 033 709 A1. On these lift trucks, the lever system consists of a reversing lever that is mounted so that it can swivel on the load section. The reversing lever is also mounted or supported on the drive section and is coupled with the linkage. Lever systems of this type, during a lifting or swiveling movement, result in a swiveling movement of the linkage (typically designed as a connecting rod or pusher rod) in which the linkages, depending on the design and construction, extend downwardly beyond the profile of the wheelarms. Lift trucks of the known art are designed for the handling of standardized “euro pallets”, which have an entry height for the wheelarms of 100 mm. Therefore, the trucks have a wheelarm height of the wheelarms in the fully lowered position in the range of approximately 85 mm.
On account of the kinematics (i.e., the required movements) of the lever system and of the linkage, a reduction of the wheelarm height to be able to handle special pallets with an entry height which is lower than that of standard euro pallets is not possible on industrial trucks of the known art to prevent the linkage from hitting the ground or roadway or during the raising and lowering of the pallet picked up on the wheelarms.
Therefore, it is an object of this invention to provide an industrial truck of the general type described above but which has improved kinematics of the linkage and makes possible a compact construction of the wheelarms with a low wheelarm height in the lowered position of the load section for handling special pallets with a low entry height.